#version 300 es
precision mediump float;
in vec2 vTextureCo;
uniform sampler2D uTexture;
const highp vec3 CO = vec3(0.2125, 0.7154, 0.0721);
out vec4 fragColor ;
void main() {
    fragColor=vec4(vec3(dot(texture( uTexture, vTextureCo).rgb,CO)),1.0);
}